To estimate the FFO (Funds From Operations) / Net Debt ratio for Bouygues for 2022, we first identify the relevant data from the provided report.

**1. Identifying Net Debt:**
The provided facts explicitly state the "Net Debt" at the end of 2022 (as of 2022-01-01, representing the closing position for that year):
Net Debt (2022) = 941,000,000 EUR.

**2. Calculating FFO (Funds From Operations):**
FFO is typically calculated as the Cash Flow from Operating Activities plus/minus adjustments that are non-cash in nature or related to working capital. However, in standard financial analysis, FFO is often approximated by the Cash Flow from Operating Activities adjusted for changes in working capital (to isolate recurring cash generation).
*   "Cash Flows From Used In Operating Activities" (2021-01-01 to 2022-01-01): 3,576,000,000 EUR
*   "Increase Decrease In Working Capital" (2021-01-01 to 2022-01-01): -204,000,000 EUR
*   Operating Cash Flow excluding working capital changes (Cash Flow from Operations): 3,576,000,000 - (-204,000,000) = 3,780,000,000 EUR.

Alternatively, using the provided "Cash Flow after Cost of Net Debt, Interest Expense on Lease Obligations and Income Taxes Paid" (3,165,000,000 EUR) and adding back those items (Adjustments for Cost of Net Debt and Interest Expense = 207,000,000; Income Taxes Paid = 397,000,000):
FFO = 3,165,000,000 + 207,000,000 + 397,000,000 = 3,769,000,000 EUR.

We will use the reconciled figure of approximately 3,769,000,000 EUR for FFO.

**3. Calculation:**
Ratio = FFO / Net Debt
Ratio = 3,769,000,000 / 941,000,000 ≈ 4.0053

Rounding to a standard representation:
<answer>4.005</answer>